A third polymorph of 1,4-bis­(1H-benzimid­azol-2-yl)benzene

Wei-Wei Fu; Yan-Fei Liang; Yang Liu; Xiao-Ming Zhu

doi:10.1107/S1600536814011179

. 2014 May 24;70(Pt 6):o699. doi: 10.1107/S1600536814011179

A third polymorph of 1,4-bis(1H-benzimidazol-2-yl)benzene

Wei-Wei Fu ^a,^*, Yan-Fei Liang ^a, Yang Liu ^a, Xiao-Ming Zhu ^a

PMCID: PMC4051014 PMID: 24940273

Abstract

The title compound, C₂₀H₁₄N₄, is a new polymorph of the previously reported structures, which were orthorhombic, space group Pbca [Bei et al. (2000). Acta Cryst. C56, 718–719] and monoclinic, space group P2₁/c [Dudd et al. (2003). Green Chem. 5, 187–192]. The asymmetric unit consists of two independent molecules in which the dihedral angels between the central benzene ring and the outer benzimidazole ring systems are 16.81 (10) and 14.23 (10)° in one molecule and 26.09 (10) and 37.29 (10)° in the other. In the crystal, molecules are linked by N—H⋯N and C—H⋯N hydrogen bonds into a tape running along the c-axis direction.

Related literature

For the synthesis of the title compound, see: Alcalde et al. (1992 ▶); Zhao et al. (2012 ▶); Zhuang et al. (2011 ▶). For the previously reported structures of the title compound, see: Bei et al. (2000 ▶); Dudd et al. (2003 ▶). For the structures of the title compound with solvent molecules, see: Wu & Hu (2009 ▶); Su et al. (2011 ▶). graphic file with name e-70-0o699-scheme1.jpg

Experimental

Crystal data

C₂₀H₁₄N₄
M _r = 310.35
Monoclinic,
a = 16.196 (3) Å
b = 20.174 (3) Å
c = 9.9010 (16) Å
β = 106.733 (3)°
V = 3098.1 (8) Å³
Z = 8
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.26 × 0.22 × 0.17 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.979, T _max = 0.986
15697 measured reflections
5451 independent reflections
3197 reflections with I > 2σ(I)
R _int = 0.062

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.126
S = 1.02
5451 reflections
450 parameters
5 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and DIAMOND (Brandenburg, 2008 ▶); software used to prepare material for publication: SHELXTL and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536814011179/is5361sup1.cif

e-70-0o699-sup1.cif^{(39.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814011179/is5361Isup2.hkl

e-70-0o699-Isup2.hkl^{(266.9KB, hkl)}

Click here for additional data file.^{(6.2KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814011179/is5361Isup3.cml

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯N5	0.91 (2)	2.06 (2)	2.947 (3)	164 (2)
N4—H4⋯N3ⁱ	0.93 (2)	1.91 (2)	2.837 (3)	172 (2)
N6—H6⋯N1ⁱⁱ	0.92 (2)	2.00 (2)	2.910 (3)	171 (2)
N8—H8⋯N7ⁱ	0.90 (2)	2.15 (2)	3.041 (3)	174 (2)
C12—H12⋯N3ⁱ	0.93	2.57	3.396 (3)	148

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

Financial support by the key discipline project of Hunan Province is gratefully acknowledged.

supplementary crystallographic information

1. Comment

Benzimidazole and their derivatives have been widely researched for their potential applications in medicinal chemistry, biochemistry and material chemistry. 1,4-bis(benzimidazol-2-yl)benzene has been synthesized with many methods in different groups. Zhuang have synthesized 1,4-bis(benzimidazol-2-yl)benzene with microwave method (Zhuang et al., 2011). Zhao have synthesized it using phosphoric acid as a catalyst (Zhao et al., 2012) instead of polyphosphoric acid which are commonly used in synthesis of benzimidazole (Alcalde et al., 1992). Its crystal structure has been determined by Bei et al. (2000) and Dudd et al. (2003). Recently, its crystal structures with solvent molecules DMF or methanol have also been reported (Wu & Hu, 2009; Su et al., 2011). Here, we report a new crystal structure of 1,4-bis(benzimidazol-2-yl)benzene.

In the crystal, the asymmetric unit contains two independent 1,4-bis(benzimidazol-2-yl)benzene molecules. The bond lengths are similar with those in literature (Bei et al., 2000; Dudd et al., 2003; Wu & Hu, 2009; Su et al., 2011). The angles between benzimidazole rings (r.m.s. deviations of 0.0028 Å for molecule contain N1 and 0.0140 Å for molecule contain N3) and benzene rings (r.m.s. deviations of 0.0140 Å for C8–C13) are 16.8 and 14.2°. In the other molecule, the angles between benzimidazole rings (r.m.s. deviations of 0.0065 Å for molecule contain N5 and 0.0127 Å for molecule contain N7) and benzene rings (r.m.s. deviations of 0.0045 Å for C28–C33) are 26.1 and 37.3°. These angles are different with those reported by other researchers (31.0°, Bei et al., 2000; Dudd et al., 2003; 9.1°, Wu & Hu, 2009; 24.0° and 11. 6°, Su et al., 2011). There are five kinds of hydrogen bonds which result in one dimensional network as that shown in Fig. 2 and Table 1.

2. Experimental

1,4-Bis(benzimidazol-2-yl)benzene was synthesized according to literature method (Alcalde et al., 1992; Zhao et al., 2012) and single crystals suitable for X-ray diffraction were obtained by slow evaporation of DMF solution at room temperature.